Diary is a 2022 Indian Tamil-language supernatural mystery thriller film written and directed by debutant Innasi Pandiyan and produced by S. Kathiresan. It was distributed by Udhayanidhi Stalin via Red Giant Movies. The film stars Arulnithi and Pavithra Marimuthu. The music and score is composed by Ron Ethan Yohann, with cinematography handled by Aravinnd Singh and editing done by S. P. Raja Sethupathi. It was shot extensively across Tamil Nadu including Chennai, Coonoor, Ooty, Mettupalayam and Coimbatore.

The film was initially scheduled to be released in theatres on 11 August 2022, but got postponed and released on 26 August 2022. The film is partially inspired by real events surrounding 13th Hair pin bend in the Indian National Highway connecting Ooty and Coimbatore and also from Bus route 375 folklore of China. The Film Ran For Over 50 Days And It Was A Blockbuster .